Room-Temperature Ferromagnetism of Graphene

Wang, Yan; Huang, Yi; Song, You; Zhang, Xiaoyan; Ma, Yanfeng; Liang, Jiajie; Chen, Yongsheng

doi:10.1021/nl802810g

Cited by 608 publications

(440 citation statements)

References 34 publications

Supporting

Mentioning

415

Contrasting

Unclassified

Order By: Relevance

“…Noble metals Au, Pt, and Rh change from conductors to insulators and from nonmagnetic to magnetic (45,46); ferromagnetism is observed in room temperature graphene and attributed to nanometer-sized defects (47). First principles calculations support the notion that singleatom defects can induce ferromagnetism in graphene (48).…”

Section: Physicsmentioning

confidence: 82%

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Shu

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

As an archetypal semimetal with complex and anisotropic Fermi surface and unusual electric properties (e.g., high electrical resistance, large magnetoresistance, and giant Hall effect), bismuth (Bi) has played a critical role in metal physics. In general, Bi displays diamagnetism with a high volumetric susceptibility (∼10 −4 ). Here, we report unusual ferromagnetism in bulk Bi samples recovered from a molten state at pressures of 1.4-2.5 GPa and temperatures above ∼1,250 K. The ferromagnetism is associated with a surprising structural memory effect in the molten state. On heating, low-temperature Bi liquid (L) transforms to a more randomly disordered high-temperature liquid (L ) around 1,250 K. By cooling from above 1,250 K, certain structural characteristics of liquid L are preserved in L. Bi clusters with characteristics of the liquid L motifs are further preserved through solidification into the Bi-II phase across the pressure-independent melting curve, which may be responsible for the observed ferromagnetism.bismuth | high pressure | ferromagnetism | melt structure B ismuth (Bi) has played important roles in metal and condensed matter physics. The extremely low carrier density of Bi allows quantum limits of the Landau level to be studied under high magnetic field (1) and quantum size effects to be observed at ∼100-nm length scale (2). At ambient condition, Bi is known to crystallize in the rhombohedral A-7 type structure (space group R-3m, D 5 3d ), with the primitive unit cell containing two atoms at positions (u, u, u) and (−u, −u, −u). Each atom has three equidistant nearest neighbors tightly bonded at a distance of ∼3.062Å (3). The Bi4 motifs form puckered bilayers ( Fig. S1A) with a thickness of 1.59Å stacked along the rhombohedral [111] direction. The distance between adjacent bilayers is 2.35Å (4), slightly smaller than the next nearest distance of 3.512Å (5). Each atom's next nearest neighbors are in the adjacent bilayers, and the bonding within each bilayer is much stronger than the interbilayer bonding. As such, Bi exhibits rather complex interatomic binding, with coexisting covalent (within the bilayers), metallic, and weaker van der Waals-like (between bilayers) bonding (4).The phase diagram of Bi is rich and complex ( Fig. 1). At ambient pressure, Bi melts at 544 K (6) with a liquid-liquid transition at 1,010 K (7). With increasing pressure, Bi undergoes structural transitions in both solid and liquid states. The A-7 structured Bi-I phase transforms successively into the monoclinic (Bi-II), incommensurate host-guest (Bi-III), and body-centered cubic (Bi-V) phases (8-10) with increasing pressure to ∼6 GPa. On pressure release, these high-pressure metallic crystalline phases are unstable and revert to the Bi-I phase. Below ∼1.6 GPa, the melting temperature of Bi-I decreases with increasing pressure, a behavior similar to that of ice. Between 1.6 and 2.4 GPa (11), the solid just below melting is the Bi-II phase, which has a similar bilayer structure to that of Bi-I, except that the distance betwe...

show abstract

Section: Physicsmentioning

confidence: 82%

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Shu

Wang

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

View full text Add to dashboard Cite

show abstract

“…Magnetism may also originate from impurity atoms which are nonmagnetic by themselves (such as hydrogen or nitrogen), but because of the specific chemical environment give rise to local magnetic moments. With regard to magnetism in graphene, 124 however, the samples were produced by annealing of graphene oxides and, surprisingly, the saturation magnetization did not correlate with the annealing temperature (a higher value for higher temperature). Moreover, no ferromagnetism was found at any temperature down to 2 K in very recent experiments 128 on magnetization of graphene nanocrystals obtained by sonic exfoliation.…”

Section: Properties Of Defective Graphenementioning

confidence: 98%

“…In addition to polymerized fullerenes, 120 nanotubes, 121 graphite, 122 and nanodiamonds, 123 magnetism was recently reported for graphene produced from graphene oxide. 124 On the basis of calculations, the observed magnetic behavior in all these systems was explained in terms of defects in the graphitic network (either native or produced by ion irradiation) such as under-coordinated carbon atoms, for example, vacancies, 125 interstitials, 126 carbon adatoms, 47 and atoms at the edges of graphitic nanofragments with dangling bonds either passivated with hydrogen atoms or free. 127 Such defects have local magnetic moments and may give rise to flat bands and eventually to the development of magnetic ordering.…”

Section: Properties Of Defective Graphenementioning

confidence: 99%

Structural Defects in Graphene

2010

View full text Add to dashboard Cite

Graphene is one of the most promising materials in nanotechnology. The electronic and mechanical properties of graphene samples with high perfection of the atomic lattice are outstanding, but structural defects, which may appear during growth or processing, deteriorate the performance of graphenebased devices. However, deviations from perfection can be useful in some applications, as they make it possible to tailor the local properties of graphene and to achieve new functionalities. In this article, the present knowledge about point and line defects in graphene are reviewed. Particular emphasis is put on the unique ability of graphene to reconstruct its lattice around intrinsic defects, leading to interesting effects and potential applications. Extrinsic defects such as foreign atoms which are of equally high importance for designing graphene-based devices with dedicated properties are also discussed.

show abstract

“…4 This underlying antiferromagnetic correlations prevent the magnetic moments, even if they develop, from ordering ferromagnetically and preclude the possibility of observing hysteresis in standard magnetic measurements. Notwithstanding, a few reports of magnetic graphite 5 and graphene 6 can be found in recent literature.…”

Section: Introductionmentioning

confidence: 99%

Hydrogenated graphene nanoribbons for spintronics

et al. 2010

View full text Add to dashboard Cite

We show how hydrogenation of graphene nanoribbons at small concentrations can open venues toward carbon-based spintronics applications regardless of any specific edge termination or passivation of the nanoribbons. Density-functional theory calculations show that an adsorbed H atom induces a spin density on the surrounding orbitals whose symmetry and degree of localization depends on the distance to the edges of the nanoribbon. As expected for graphene-based systems, these induced magnetic moments interact ferromagnetically or antiferromagnetically depending on the relative adsorption graphene sublattice, but the magnitude of the interactions are found to strongly vary with the position of the H atoms relative to the edges. We also calculate, with the help of the Hubbard model, the transport properties of hydrogenated armchair semiconducting graphene nanoribbons in the diluted regime and show how the exchange coupling between H atoms can be exploited in the design of novel magnetoresistive devices.

show abstract

Room-Temperature Ferromagnetism of Graphene

Cited by 608 publications

References 34 publications

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Deep melting reveals liquid structural memory and anomalous ferromagnetism in bismuth

Structural Defects in Graphene

Hydrogenated graphene nanoribbons for spintronics

Contact Info

Product

Resources

About